what age to sit in front seat

Short version: in Australia, kids under 4 must not sit in the front seat if the car has two or more rows.

Ages 4–7 can only ride up front if all rear seats are already occupied by children under 7, and they must use an approved booster with a lap‑sash belt where available.

From 7 years onward it’s legal to sit in the front, but safety boffins still recommend the back seat until at least 12 because airbags and little noggins aren’t the best of mates.

No, “they’re tall for their age” doesn’t change the law; use the correct restraint for their size and check your state’s road authority for any local quirks.